Package: Active Optics
Description: Focusing and centering
correction of M2
Package name: act
Inheritance: Standard Package
Deployment: AT Control Workstation: atactControl process.
Use Case diagram:
Class diagram:
Architecture:
This package is responsible for correction of M2 focus/centering.
There are two architectures to achieve M2 corrections
Open-loop correction
The open-loop (or "look-up") correction adjusts M2 focus/centering according to altitude angle
and temperature using calibrated data.
The calibration data is processed on the workstation and positions are sent to M2.
The following commands are dedicated to the open loop correction:
- ONECAL: Do one calibrated correction
- CYCLCAL: Do cyclical calibrated corrections
Closed-loop correction
In this case a defocus signal to be delivered by STRAP via astigmatism measurement
is used to derive the corrections of M2 and the loop is closed.
The following commands are dedicated to the open loop correction:
- ONEIA: Do one image analyis
- CYCLAO: Do cyclical closed-loop active optics
Reuse from VLT TCS: 30%
For more details see the Active Optics Design Description document[RDV14].
Issues to be Determined or Resolved:
Last modified: Tue Jun 26 14:42:30 UTC 2001